Quiet 4 stroke exh?

[kell8071]

Sorry to bring back an old one but I'm still interested in finding a turn down that has minimal impact on sound or at least sound traveling longer distances. From what I can gather people have tried turn downs with piping that are similar in size to the muffler inner diameter. Has anyone tried using a larger sized pipe? I'm wondering if the turn down could be made out of larger diameter pipe to avoid limiting restriction but still redirect any noise towards the snow? It might look a little silly but so did the old DB Snorkel...

The attached image is pretty crude but is a cross-section of what I was thinking. The top hat would mount to the muffler using the hole FMF has for the spark-arrestor or quiet insert. The pipe would mount to it. It would probably need some additional support as well but that's for another day...

Just a thought however if its already been tried I wouldn't mind skipping the wasted effort.



Thanks,
Kell

 

[eric82930]

I did that to mine and it worked great. I welded it on. Almost exactly the shape in your drawing.

 

[kell8071]

I did that to mine and it worked great. I welded it on. Almost exactly the shape in your drawing.

Any recollection what size pipe you used?

Thanks!

Kell

 

[BendBrapp]

I’ve been happy with my turn down. Had the local exhaust artist bend and weld a stainless oversized section and weld it to the stock sx end cap. It was done for two reasons originally. 1st was to reduce the ice ball and cooking of my spare gas. 2nd was the hope it would knock down some of the noise. It achieved both with no loss of power or response I could detect.

 

[powdermuncher]

I have been looking at going 2 stroke for just the noise 4 strokes are annoyingly loud and I dislike the 4 stroke sound. At the same decibel level two stroke noise does not nearly travel as far as a 4 stroke thumper. A Turbo is definitely much quieter as it smoothens out the power pulls of the thumper as well. Any Header with a expansion chamber on it cuts down the noise by a couple decibels. That is the reason the 2 stroke exhaust usually carries less the pipe dampens down the hard edge exhaust pulses. I will also try a 45 degree downturn at about 2 times the diameter of the exhaust outlet on my thumper. Hopefully it will not loose to much power that way.

 

[powdermuncher]

On a side note I have tried tunnel dumps on a few sleds and the back pressure can be significant the bike would most likely loose a ton of power in deep snow. Never a problem on the trail but they often bog down in the pow.

 

[kell8071]

I have been looking at going 2 stroke for just the noise 4 strokes are annoyingly loud and I dislike the 4 stroke sound. At the same decibel level two stroke noise does not nearly travel as far as a 4 stroke thumper. A Turbo is definitely much quieter as it smoothens out the power pulls of the thumper as well. Any Header with a expansion chamber on it cuts down the noise by a couple decibels. That is the reason the 2 stroke exhaust usually carries less the pipe dampens down the hard edge exhaust pulses. I will also try a 45 degree downturn at about 2 times the diameter of the exhaust outlet on my thumper. Hopefully it will not loose to much power that way.

I ordered 2.5" SS pipe that I'm going to try. The exhaust diameter is 1.8" so hopefully that's enough to prevent restriction yet redirect the sound. It's going to look pretty stupid but whatever. The current Powercore 4 is sooo loud I need to do something.

Kell